13/2×6-13/2+13/2
=13/2×(6-1+5)
=13/2×10
=65
13/18×5.16+51.6×1/36
=5.16×(13/18+10/36)
=5.16×1
=5.16
9-5/6×9/20-5/8
=9-3/8-5/8
=9-(3/8+5/8)
=9-1
=8